1. Field of the Invention
The present invention relates to chord detection techniques for electronic musical instruments, in particular, for detecting chords upon operation of hand and foot keyboards.
2. Description of the Related Art
Some electronic musical instruments have a hand keyboard for hand operation, and a foot keyboard for foot operation. The hand keyboard has dual keyboards, so that the upper keyboard is used to play a melody line, and the lower keyboard is used to play a chord line. In an electronic musical instrument having an automatic accompaniment function, chord detection is made upon operation of the lower keyboard and foot keyboard, and an automatic accompaniment according to the detected chords is made. An example of a chord detection method is described in Japanese Patent Publication No. 5-84920 (Japanese Patent Laid-Open No. 62-186298).
Chords to be detected are categorized into fraction chords (e.g., C/B), and normal chords which are not fraction chords. In a fraction chord, a numerator chord is that of an upper part (corresponding to the hand keyboard) of a music score, and a denominator chord is that of a lower part (corresponding to the foot keyboard) of the music score.
An electronic musical instrument detects chord roots of the hand and foot keyboards. When the chord root detected at the hand keyboard is different from that detected at the foot keyboard, a fraction chord (e.g., C/B) is detected. Conversely, when the chord root detected at the hand keyboard is the same as that detected at the foot keyboard, a normal chord which is a not a fraction chord is detected. However, this method cannot always precisely detect a chord, and an inappropriate chord may often be detected.
It is an object of the present invention to detect an appropriate chord in accordance with operations of hand and foot keyboards.
According to one aspect of the present invention, there is provided a chord detection apparatus for an electronic musical instrument, comprising a hand keyboard for hand operation, a foot keyboard for foot operation, a hand-keyboard detection unit for detecting a temporary hand-keyboard chord root and a temporary hand-keyboard chord type in accordance with operation of the hand keyboard, a foot-keyboard detection unit for detecting a temporary foot-keyboard bass root in accordance with operation of the foot keyboard, and a determination unit for determining a true chord root and chord type, and the presence/absence of a bass root in accordance with the temporary hand-keyboard chord root, hand-keyboard chord type, and foot-keyboard bass root.
According to another aspect of the present invention, there is provided a chord detection method for an electronic musical instrument having a hand keyboard for hand operation, and a foot keyboard for foot operation, comprising (a) the step of detecting a temporary hand-keyboard chord root and a temporary hand-keyboard chord type in accordance with operation of the hand keyboard, (b) the step of detecting a temporary foot-keyboard bass root in accordance with operation of the foot keyboard, and (c) the step of determining a true chord root and chord type, and the presence/absence of a bass root in accordance with the temporary hand-keyboard chord root, hand-keyboard chord type, and foot-keyboard bass root.
According to still another aspect of the present invention, there is provided a recording medium that records a program for an electronic musical instrument having a hand keyboard for hand operation, and a foot keyboard for foot operation, the program making a computer execute (a) a sequence for detecting a temporary hand-keyboard chord root and a temporary hand-keyboard chord type in accordance with operation of the hand keyboard, (b) a sequence for detecting a temporary foot-keyboard bass root in accordance with operation of the foot keyboard, and (c) a sequence for determining a true chord root and chord type, and the presence/absence of a bass root in accordance with the temporary hand-keyboard chord root, hand-keyboard chord type, and foot-keyboard bass root.
According to the present invention, a temporary hand-keyboard chord root and a temporary hand-keyboard chord type are detected in accordance with operation of the hand keyboard, and a temporary foot-keyboard bass root is detected in accordance with operation of the foot keyboard. Since these chords are used as temporary ones, and a true chord root and chord type, and the presence/absence of a bass root are determined later in accordance with the temporary hand-keyboard chord root, hand-keyboard chord type, and foot-keyboard bass root, an appropriate chord can be detected.